use enum for meta commands

When Who What
2017-11-02 22:32:32 Tom Lane (tgl) Closed in commitfest 2017-11 with status: Committed
2017-11-02 22:11:52 Tom Lane (tgl) Added tgl as committer
2017-11-02 14:29:18 Aleksandr Parfenov (a.parfenov) Posted review with messageid <20171102142918.1328.12179.pgcf@coridan.postgresql.org>
2017-11-02 14:29:18 Aleksandr Parfenov (a.parfenov) New status: Ready for Committer
2017-11-01 13:40:42 Aleksandr Parfenov (a.parfenov) Added a.parfenov as reviewer
2017-09-23 03:49:33 Fabien Coelho (calvin) Changed authors to Fabien Coelho (calvin)
2017-09-23 03:49:22 Fabien Coelho (calvin) Attached mail thread alpine.DEB.2.20.1709230538130.4999@lancre
2017-09-23 03:49:21 Fabien Coelho (calvin) Created patch record